Paper maps and charts used for navigation almost always have several important pieces of information printed in the margins or on the map or chart itself. One of these pieces of information is the scale, usually written as a number like 1:24,000 (read as "one to twenty-four thousand"). This number tells the user how to measure a distance in the real world based on a measurement from the chart or map. In the example 1:24,000 this means that one inch on your map is equal to 24,000 inches on the ground (or water). Since 24,000 inches are equal to 2,000 feet, that means one inch on your map is equal to 2,000 feet.